In recent years, the demand for flat panel display (FPD) devices has been increasing. In particular, organic EL display devices which use an organic EL (Electro Luminescence) element (OLED; Organic Light Emitting Diode) are excellent in terms of power consumption, lightness, thinness, video properties and viewing angle, and the development and practical use of such devices is progressing. Since the high definition of organic display panels in organic EL display devices used in smartphones is progressing, the increase in power consumption that accompanies this trend is becoming a problem. However, a high definition display is not necessary in various situations and It is sometimes sufficient to display only basic data such as time and date, the state of the device (signal strength, remaining battery), or communication data (call history, mail inbox). However, sub-screens such as those mounted in conventional mobile phones are not mounted in organic EL displays, in smartphones, it is necessary to operate a large screen organic EL display panel even when displaying a small amount of data. And, that leads to an increase in power consumption.
While partial driving for reducing power consumption has been proposed in liquid crystal display devices for mobile phones, the power consumption of illumination devices which act as a light source in liquid crystal devices is overwhelmingly large and power reduction effects are few. When partial driving is applied to a display device in which power consumption increases according to display gradation and the number of display pixels as in organic EL display panels, the reduction effects of power consumption are considerable. However, in organic EL display panels, when partial display is performed using partial driving, organic EL elements which are continuously displayed deteriorate and screen burn-in occurs. In order to avoid these problems, when an image is input as a usual operation from the host side in order to change the position of the image, there is a problem that power consumption on the host side increases. Furthermore, although “a method for preventing screen burn-in by performing display in a different position to a previous display position stored in advance at the time of initializing power” has been proposed in Patent Document 1 (Japanese Laid Open Patent 2006-211044), the prevention effects of screen burn-in are limited since the power initialization cycle cannot be controlled.